Study finds no significant associations between donor BMI and GvHD after HCT

A study by Lucie Turcotte, University of Minnesota Blood and Marrow Transplant Program, Minneapolis, and colleagues, evaluated if there were associations between donor body mass index (BMI) and graft-versus-host-disease (GvHD). The authors noted that more than one-third of hematopoietic cell transplantation (HCT) donors are obese but there have not yet been any studies to examine the outcomes. The results of the analysis were published in Bone Marrow Transplantation in July 2018.

Study Overview

• Data was taken from the Center for International Blood and Marrow Transplantation Research (CIBMTR)
• Patients included in the study (N = 4412) had a diagnosis for acute lymphoblastic leukemia (ALL) (n = 14.4%), acute myeloid leukemia (AML) (n = 54.4%), chronic myeloid leukemia (CML) (n = 7.8%) or myelodysplastic syndrome (MDS) (n = 23.4%). Patients had HLA-A, B, C and DRB1-matched unrelated peripheral blood stem cell transplants between 2000-2013
  • The median age of patients at the time of transplant was 52 years (range, 0–79)
  • The median age of donors was 32 years (range, 18–62)
• The donor BMI categories consisted of underweight (BMI < 18.5 kg/m²), normal weight (18.5–24.9 kg/m²), overweight (25–29.9 kg/m²), obese (30–39.9 kg/m²) and morbidly obese (≥40 kg/m²)
• The primary endpoints of the study were incidence of grade II-IV and grade III-IV acute GvHD (aGvHD) and chronic (cGvHD). Secondary endpoints included; relapse, disease-free survival (DFS), non-relapse mortality (NRM), and overall survival (OS)
• P < 0.01 was considered as the threshold for significance in this study

Key Findings

• The univariate analysis suggested that there was no significant difference between the donor BMI categories and the cumulative incidence of grade II-IV aGvHD at Day 100 (P = 0.59) or grade III-IV aGvHD at Day 100 (P = 0.76)
• There was no significant difference between the cumulative incidence of cGvHD and donor BMI at one year (P = 0.15) and two years (P = 0.28)
• Cumulative incidence of NRM at 2 years was not significantly different across donor BMI categories (P = 0.04)
• Relapse at 2 years did not differ significantly between categories of donor BMI (P = 0.18)
• There was no significant difference between 2-year DFS and donor BMI (P = 0.18) and 2-year overall survival (P = 11)

The authors concluded that from their study there were no consistent and significant trends to suggest that donor BMI was associated with aGvHD, cGvHD, relapse, DFS, NRM or OS. Although there was a limited number of morbidly obese donors, donor obesity was not considered a risk for GvHD or other adverse outcomes of HCT.